In most cases, law enforcement will ask you to submit to a BAC (blood alcohol concentration) test when arresting you for a DWI in Texas. Typically, the arresting officer must inform you of the consequences if you refuse a breath test, including a mandatory license suspension and the potential of a warrant to take your blood by force. Increasingly, people are refusing the breathalyzer test in favor of the blood test because they’ve heard the breath test is the less reliable of the two. Unfortunately, neither the blood or breath BAC tests are foolproof, but each has its pros and cons. Making the right decision when arrested for a DWI takes understanding both.

Breath Tests

Breath chemical tests are taken using a breathalyzer device. They analyze samples of “deep lung” or alveolar air from the alleged offender’s breath. The science behind breathalyzers assumes the evaporated alcohol in your breath is a direct reflection of that in your bloodstream, meaning the results are viewed interchangeably. In reality, breath tests are generally less accurate than blood tests because they do not directly measure blood alcohol content. Instead, they measure breath alcohol. They are also not conducted by trained laboratory professionals, as blood tests are.

Many factors can produce false positives in breath tests, such as your state of health, what medications you take, what you recently consumed or even what type of diet you are on. The unfortunate truth is if you submit to a breath test, the results might not be reliable. A seasoned Texas DWI attorney can usually challenge breath test results, however, as there are many known weaknesses in breath test science.

Blood Tests

Blood tests are run using a blood sample from the alleged offender. Blood draws are supposed to be taken by trained personnel in a laboratory environment. They must also be preserved, stored and analyzed according to a certain procedure. These stringent standards reduce the risk of degradation or contamination of the sample. Because BAC can be directly measured using a blood sample, many argue blood tests are more accurate and thus should be chosen over breath tests. It’s true; blood tests eliminate some of the varying factors that can produce false positives in breath tests. It may be more difficult, however, to challenge blood test results if you think they are inaccurate.

While neither the breath or the blood BAC test is 100% accurate, the good news is, regardless of which you took, an attorney might be able to help challenge the results. In an ideal situation, it’s best to consult with a Dallas DWI defense attorney before agreeing to submit to a breath or blood test. If you already took one or refused to submit to one, speak with a highly experienced Dallas DWI defense attorney about the consequences. Again, blood draws can be forced in some instances. Also, you face an automatic license suspension if you refuse to submit to a test. Discuss the details of your case with a DWI defense attorney to learn about the consequences you could face and how you can challenge the results of a BAC test.

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